1. Field of the Invention
The present invention relates to apparatus and methods for producing patterned soft gelatin capsules.
2. Background of the Art
Capsules are solid dosage forms in which therapeutic agents are enclosed in a soluble gelatin wall. The wall can be made of either soft or hard gelatin. Soft gelatin capsules ("SGC" or soft gels) comprise a soft, globular, gelatin wall. The gelatin may be plasticized by the addition of additives such as glycerin, sorbitol, or a similar types of polyols. Soft gelatin capsules offer a convenient dosage form for the administration of drugs, nutrients, vitamins, foodstuff and cosmetics.
Commercially available SGCs come in a wide choice of sizes and shapes, e.g., they may be round, oval, oblong, tubular or suppository-shaped. These SGCs are formed by joining two identical halves to form a shell encapsulating a fill.
Upon ingestion by the consumer (or on contact with water), moisture causes the capsule to come apart at the seams where the two halves are joined thereby releasing the fill or contents of the capsule.
SGCs are generally prepared by one of two methods. The first method is known as the plate process. In this method, a set of molds is used. A warm sheet of gelatin is laid over a lower plate and the liquid fill is poured on it. A second sheet of gelatin is then placed on top followed by the top plate. The set is placed under pressure to form the desired capsule. The sheets of gelatin used to form the capsule may be colored or uncolored.
In 1933, Robert P. Scherer invented the rotary-die process. In this process, soft gelatin capsules are made by continuously casting two separate ribbons of molten or flowable gelatin into two separate rotating dies of an encapsulation machine to produce soft, elastic gelatin capsules. Dyes or other suitable coloring material can be added to the molten gelatin to produce soft gelatin capsules of various colors. In addition, if different dyes are added to the different molten gelatin masses then softgels with halves of different colors can be made. A more detailed description of the well known soft gelatin capsule art may be found in Ebert, "Soft Elastic Gelatin Capsules: A Unique Dosage Form," Pharmaceutical Technology. October 1977 and in "The Theory and Practice of Industrial Pharmacy", Chapter 13, Lachman et al., published by Lea and Febiger, 1970. The rotary die process described in these references are incorporated herein by reference as being descriptive of the rotary die process to which the present invention is related.
The art also teaches applying identifying marks to the exterior surface of the capsule shell. Specific examples of known processes and machines used for applying some type of identification on softgels are shown, for example, in U.S. Pat. No. 2,449,139; Scherer U.S. Pat. No. 2,623,494; Scherer U.S. Pat. No. 2,688,775; Taylor U.S. Pat. No. 3,124,840; Hansen U.S. Pat. No. 3,203,347; and Vincent U.S. Pat. No. 3,333,031.
Scherer U.S. Pat. No. 2,623,494 relates to a banding machine for softgels. In this machine, the identifying band is applied to each individual capsule after the capsule is formed.
Scherer U.S. Pat. No. 2,688,775 shows a method for applying a brand to the exterior surface of a gelatin capsule.
Scherer U.S. Pat. No. 2,703,047 discloses a similar system of branding the filled capsules.
In Taylor U.S. Pat. No. 3,124,840, a printing element is provided in order to print on the gelatin strip prior to the formation of the capsule.
Hansen U.S. Pat. No. 3,203,347 shows a marking fluid that is printed on the gelatin ribbon used to make the softgels.
Vincent U.S. Pat. No. 3,333,031 shows dyeing of the gelatin strip before formation.
Scherer U.S. Pat. No. 2,596,176 teaches a method as well as an apparatus for striping gelatin capsules. In this method, gelatin capsule is grasped at its ends, successive contiguous parts of the capsule are abraded and, as the parts are being abraded, colors are applied.
German Patent No. 3,818,071 discloses processes for printing on the gelatin ribbons or strips used to manufacture soft gelatin capsules.
In the early 1960's, R. P. Scherer in Canada produced and sold soft gelatin capsules made by the so-called "swirl" method. In the swirl method, two different colors of molten gelatin were fed into a single spreader box. The two different colors of gelatin were then allowed to intermingle or swirl and then to simultaneously flow through the opening at the bottom of the spreader box to form a patterned gelatin ribbon. However, because only a single spreader box was used, the exact nature of the pattern was difficult to control. Applicant has been unable to determine whether capsules made by the "swirl" method were ever commercialized within the United States.
The prior apparatus and methods for making soft gelatin capsules have failed to provide a convenient, easy to use, reproducible apparatus and method for producing patterned soft gelatin capsules, such as striped capsules. The prior methods have been unsatisfactory, such as those that merely printed patterns on the exterior surface of the gelatin ribbon, laborious, such as the abrasion method disclosed in Scherer U.S. Pat. No. 2,596,176, or lack reproducibility. There is a need in the art for an apparatus and method to solve these problems.